In automotive ventilating systems, and in ventilating systems generally, there exists a need to direct air within and through an HVAC unit to provide appropriate heating and cooling temperatures as finally desired, through respective air pathways. Air can be directed by dampers, doors, and various mechanisms to wherever the ventilating system designer would like the air to proceed, and under any selected design condition. For example, in a vehicle it is desirable to provide for components, and, in particular, plastic or plastic like components, to be located within the HVAC housing, and, in particular, between and within the housing portions of the HVAC unit. In the majority of automotive HVAC units, the HVAC unit comprises two distinct major portions or housing ‘halves’ which need to be attached or ‘fastened’ together in some fashion to provide for a complete HVAC unit housing.
The HVAC design or architecture is limited by a number of requirements. For example, components such as described above must be provided with an air sealing around the components that relate to forces or pressure points that are found distributed along contact points or ‘patches’ where two housing portions contact each other. Typically, sealing features such as tongue and groove air sealing features, are found at the area of the contact patch as the seal that is found between the housing requires a force normal to it to ensure that the housing are sealed properly.
In addition to contact patches where two housing portions contact each other, traditional HVAC unit architectures often have contact points at or near the center of the housing of a smaller surface area than those found at other areas of the housing portions such as the outer walls. Such smaller contact areas are typically found at an end of the heater core, for example, and are necessary to provide normal seal forces in these areas. In order to ensure that the seal forces in these areas are normal and adequate, HVAC housing are typically designed with a prescribed region or ‘tower’ located or incorporated into the plastic component that is large enough to allow a screw to be inserted from outside the housing portions through the housing portions to fasten the housing portions together, thereby providing for normal seal forces in the contact areas.
The tower concept, while producing the desired effect of allowing the forces to be normal along the contact areas, has a number of disadvantages. Current state of the art provides for a tower with a screw boss and/or locator pin to force the two walls together. The screw, therefore, typically enters into a ‘well’ or ‘fosse’ in the housing for assembly. The tower requires screw driver tool access from the external side of the housing and therefore requires more packaging space and a thin tower in the plastic mold. See FIG. 1.
The mold tool for the plastic component that forms the tower, for example, is required to be designed to provide for an often tall and thin mold to produce the tower feature. The resultant tool also has the disadvantage of being costly to produce and of having limited life due to the extraordinary features related to the tower.
The prior art has many complex devices for fastening portions of housings in automobile mounted HVAC systems. However, the complexity only adds cost to the design process, adds cost to the manufacture, and further increases, rather than decreases, overall space requirements of the HVAC unit.
The present invention, by providing for an alternative attachment or fastening means without the need for such as tower, overcomes the problems found in the prior art.